Arctoa (2018) 27: 18–28 doi: 10.15298/arctoa.27.02 MOSS FLORA OF THE UST-NERA REGION IN THE UPPER COURSE OF INDIGIRKA RIVER, EAST YAKUTIA ФЛОРА МХОВ ОКРЕСТНОСТЕЙ УСТЬ-НЕРЫ, ВЕРХНЕЕ ТЕЧЕНИЕ ИНДИГИРКИ, ВОСТОЧНАЯ ЯКУТИЯ ELENA I. IVANOVA1, ELENA A. IGNATOVA2, VERA G. ISAKOVA1, ILYA A. BALAKIREV3, OXANA I. KUZNETSOVA4, MICHAEL S. IGNATOV2,4 ЕЛЕНА И. ИВАНОВА1, ЕЛЕНА А. ИГНАТОВА2, ВЕРА Г. И САКОВА1, ИЛЬЯ А. БАЛАКИРЕВ3, ОКСАНА И. КУЗНЕЦОВА4, МИХАИЛ С. ИГНАТОВ2,4 Abstract List of 162 moss species collected in the Ust-Nera region (Oimyakon District) is presented. It includes some interesting records of xeric species growing on steep steppe slopes on the banks of Indigirka River and its tributary, Nera River, i.e., Hilpertia velenovskyi and Pterygoneuron kozlovii. In the mountain tundra communities on Taas-Kystabyt Mt. Range (Chersky mountain system) two rare species were found. For Grimmia fuscolutea it is the fifth locality in Russia; it was previously known in the Caucasus, Altai, Baikal Lake area and Kamchatka. Finding of the suboceanic species, Pseudo- taxiphyllum elegans, in the area with severely continental climate is quite unexpected; its identity is confirmed by molecular markers. Резюме В окрестностях поселка Усть-Нера (Оймяконский улус) собрано 162 вида мхов. Среди них есть интересные находки ксерофитных видов на сухих степных склонах по берегам Индигирки и ее притока, р. Неры, в том числе Hilpertia velenovskyi и Pterygoneuron kozlovii. На хребте Таас- Кыстабыт, входящем в горную систему Черского, были найдены два редких вида мхов. Для Grimmia fuscolutea это пятое местонахождение в России; ранее этот вид был известен из еди- ничных мест на Кавказе, Алтае, в районе озера Байкал и на Камчатке. Находка субокеанического вида Pseudotaxiphyllum elegans в районе с резко континентальным климатом оказалась весьма неожиданной; его генетическое сходство с образцами из других регионов подтверждено с помощью молекулярных маркеров. KEYWORDS: bryophytes, biodiversity, phytogeography, Pseudotaxiphyllum INTRODUCTION concentrated on tundro-steppe communities occurring on Moss flora of an extensive territory of Yakutia still south-facing slopes. This list comprised 52 moss species, remains rather unevenly studied. One of its poorly in- including some newly recorded xeric mosses, such as vestigated areas, near Ust-Nera settlement, is in the fo- Pterygoneurum kozlovii. cus of the present paper. It remained hardly accessible In the present paper, the results obtained mainly dur- until recently, when the new branch of Magadan Hwy ing a brief field trip are summarized. The majority of was built. specimens were collected in several localities around Ust- The only data on mosses for the middle course of In- Nera settlement (Fig. 1) in 2015, July 31 to August 7, digirka River was published by Afonina et al. (1979) for with few additional samples collected by one of the au- the In’yali Creek area, about 80 km downstream Indigir- thors (IB) later on. The resulting list is obviously not ka River from the study area. It was based on collections exhaustive; however, it includes a number of new and made by O.M. Afonina in the course of Polar expedition interesting records and fills a gap in our knowledge of of Komarov’ Botanical Institution; this study especially bryophyte flora of Yakutia. 1 – Institute for Biological Problems of Cryolithozone of Siberian Division of Russian Academy of Sciences, 41 Lenin ave., Yakutsk, 677000, Russia – Россия 677000 Якутск, пр. Ленина, д. 41, Институт биологических проблем криолитозоны СО РАН; e-mails: [email protected] & [email protected] 2 – Lomonosov Moscow State University, Biological Faculty, Geobotany Dept., Leninskie Gory Str. 1-12, Moscow 119234 Russia – Россия, 119234, Москва, Ленинские Горы, д. 1 стр. 12, Московский государственный университет, биологический факультет, кафедра геоботаники. E-mails: [email protected] & [email protected] 3 – Yst-Nera Gymnasium, Kommunisticheskaya, 17, Ust-Nera, Yakutia, Russia. – Россия, Якутия, Оймяконский район, Усть- Нера, Коммунистическкая 17, Усть-Нерская Гимназия. E-mail: [email protected] 4 – Tsitsin Main Botanical Garden, Russian Academy of Sciences, Botanicheskaya Str., 4, Moscow 127276 Russia – Россия 127276 Москва, Ботаническая 4, ГБС РАН. E-mail: [email protected] Moss flora of the Ust-Nera, Yakutia 19 Fig. 1. Collecting localities in the upper course of Indigirka River near Ust-Nera Settlement (see also Table 1). Table 1 Collecting localities near Ust-Nera Settlement (at 64°25' – 64°42'N, 142°7' – 144°21'E ). Locality Collectors and years of collecting Altitude, m Lat Long 1. Surroundings of Ust-Nera Settlement Ignatov, Ignatova, Ivanova, 2015; 460–770 64°33' – 142°7' – Balakirev, 2016, 2017 64°34' 142°15' 2. Ol’chan Pass at 32 km NW of Ust-Nera Ignatov, Ignatova, Ivanova, 2015 1100 64°38' 142°34' Settlement 3. 40 km NW of Ust-Nera Settlement Ignatov, Ignatova, Ivanova, 2015 900 64°39' 142°’32' (Tuora-Tas Creek) 4. Ol’chan gold works Ignatov, Ignatova, Ivanova, 2015 785 64°42' 142°34' 5. 25 km SE of Ust-Nera Settlement, Ignatov, Ignatova, Ivanova, 2015; 1260–1600 64°27' 142°35' Taas-Kystabyt Mt. Range near Nelkan pass Balakirev, 2016, 2017 6. Nera River valley at ca. 30 km E Ignatov, Ignatova, Ivanova, 2015 570 64°30' 143°43' of Ust-Nera Settlement 7. 40 km E of Ust-Nera Settlement, Ignatov, Ignatova, Ivanova, 2015 570 64°25' 144°02' Mekcherge Creek mouth 8. Ca. 60 km E of Ust-Nera Settlement, Ignatov, Ignatova, Ivanova, 2015 600–750 64°27' 144°21' Topol’ Creek mouth STUDY AREA ing ca. 300 km long; it flows in northwest direction, cross- The explored territory is situated in the upper course ing zones of different geological structure (Rusanov et of Indigirka River, near the Nera River mouth. Its bryo- al., 1967). phytes have been collected in several localities within Climate of the study area is severely continental; this In’yali-Olchan Upland, Mt. Range Taas-Kustabyt (Sary- place is close to Oimyakon Settlement, where the coldest chev), Indigirka River valley up to ca. 10 km upstream temperature among lowlands in the Northern Hemi- Ust-Nera Settlement, and the valley of Nera River, up to sphere, –67.7°C, was recorded in 1938. According to the ca. 60 km from its mouth (Fig. 1, Table 1). Nera meteostation data (by four years of observation), Geologically, the In’yali-Olchan Upland comprises the mean annual temperature is –14.6°С; winter lasts numerous small massifs of igneous rocks and intrusions. more than 7 months, with the number of days with snow Taas-Kystabyt Mt. Range is rather monolithic (with max- cover 2 13; lowest temperature –57.3°С; highest temper- imal altitude of 2341 m), formed mainly by aleurolite ature 33.9°С; annual precipitation 230 mm (Table 2). and argillite interrupted by granite intrusions. Nera Riv- This area is xeric, with precipitation to evaporation ratio er is one of the largest tributaries of Indigirka River, be- being 0.2–0.15. 20 E.I. IVANOVA, E.A. IGNATOVA, V.G. ISAKOVA, I.A. BALAKIREV, O.I. KUZNETSOVA, M.S. IGNATOV A B C D E F G H Fig. 2. A: a view of Chersky Mt. System from Ol’chan pass; B: Indigirka River valley near Ust-Nera Settlement; C: bridge across Indigirka River; D: steppe on the right steep slope of Indigirka River; E: mesotrophic mire in the valley of Nera River; F: weathered rocks on the ridge top of Tas-Kystabyt Mt. Range; G: Ol’chan gold works and mine dumps; H: Coscinodon hartzii on rocks rich in heavy metals. Moss flora of the Ust-Nera, Yakutia 21 Table 2. Meteorological data for Ust-Nera and neighboring meteostations for 1987–1990 (Meteorological annual, 1987-1990). Meteostations tann tmax tmin tJanuary tJuly Annual preci- Days with Maximal depth pitation, mm snow cover of snow cover, cm Ust-Nera –14.6 33.9 –57.3 –48.6 16.9 230.0 213 44 Predporozhnaya –14.0 34.8 –55.6 –44.9 17.5 174.5 212 27 Agayakan –15.7 30.7 –56.6 –48.2 15.0 196.7 231 42 Oimyakon –16.5 31.0 –57.9 –49.4 14.9 205.5 226 41 The study area belongs to the territory with continu- Zone of lichen tundra is weakly expressed and quickly ous permafrost. Cryomorphic structures play a signifi- transits into rocky cold deserts. cant role in all relief elements. Soil cover is peculiar, lack- Within the forest belt, open larch forests occupy the ing any podsol-forming processes. Strongly acidic thixo- largest area on mountain slopes. On south-faced slopes, tropic gley soils prevail. In river valleys, peat boggy and they do not exceed an altitude of 650–700 m and are rep- meadow-boggy soils occur at places, while under steppe resented by redberry-moss forests with Aulacomnium tur- vegetation chernozem-like soils are formed (Karavaev & gidum (80–90%) and small admixture of other moss spe- Dobretsova, 1964). cies. Closer to subgoltsy zone shrublet-lichen larch for- Nera River, a right tributary of Indigirka River in its ests develop; they have poor moss layer (cover 10–20%) upper course, crosses the highland with sharply ex- formed by Aulacomnium turgidum, Polytrichum strictum, pressed altitudinal zonation. Up to 600–650 m a.s.l., and Rhytidium rugosum. On north-faced slopes, boggy belt of open forests of Larix cajanderi is situated; in the larch forests with Sphagnum and lichens usually grow; interval from 650 to 1100 m it gives way to mountain they often have hillocky relief formed as a result of cryo- forest-tundra zone, and further up zone of subgoltsy genic processes (hillock height is up to 50 cm). In such shrubs, mountain tundra and cold deserts occur. forests, frozen soil is observed in the end of summer di- In the valley of Nera River in its middle and lower rectly under Sphagnum layer.